Sustainable highly elastic hydrogels made from naturally-derived materials for biomedical applications

Lignin is second most abundant biopolymer on Earth, accounting for around 30% of the organic carbon in the biosphere¹. It is widely used in the papermaking industry where more than 85% of the 50 to 70 million tons of the lignin used worldwide annually is degraded into alkali lignin². This compound is biocompatible, biodegradable, has a high carbon content, low density, as well as antioxidant, antimicrobial, anti-ultraviolet, and stabilizing properties³. However, it is underutilized as approximately 98% of industrial lignin is simply discarded or burnt as a low-grade burning fuel⁴. Using alkali lignin for high-value applications is a great way to revalorize this resource. Here we describe the study of an innovative class of alkali lignin – gelatin hydrogels based on electrostatic interactions. These hydrogels display great elasticity, tunable mechanical properties and stability. Their low-cost, ease of production and biocompatibility are rarely seen for highly elastic hydrogels, with great potential biomedical applications.